Polymeric hardeners for gelatin



United States Patent 3,277,030 POLYMERIC HARDENERS FOR GELATIN Louis M.Minsk and Hyman L.'Cohen, both of Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N .Y., acorporation of New Jersey No Drawing. Original application Aug. 6, 1962,Ser. No. 214,815. Divided and this application Oct. 8, 1965, Ser. No.516,180

3 Claims. (Cl. 2608) This invention relates to hardeners for gelatineither when used as such or when used as the carrier for silver halidein photographic emulsions. These hardeners are polymeric in form andcontain both carboxyl and unsaturated hydrocarbon aldehyde ormaleimido-radicals. This application is a division of our copendingapplication Serial No. 214,815, filed August 6, 1962, now abandoned.

Various hardeners for gelatin have been suggested such as in thepreparation of photographic products. Many photographic products containseveral gelatin layers in sandwich form and it is often desirable todifferentially harden these layers to a different degree determined bythe task that each layer is to perform. The simple organic hardeners areprone to migrate from layer to layer, hence, ditferential hardening isdiflicult to achieve. As a result of this migration, the various layersof the photographic products tend to harden equally.

One means of anchoring the hardening function in a compound to be usedfor this purpose has been to unite a radical or grouping of highmolecular weight with a radical or grouping of lower molecular weightwhich exerts a hardening eiiect. In the present invention, theprevention of migration is achieved by the use of a polymeric hardenerin the gelation composition.

One object of our invention is to provide hardeners for gelatin whichresist migration from the layer in which they are present to an adjacentlayer. Another object of our invention is to provide polymeric hardenersfor gelatin having a polymeric chain which acts as a ballast forhardening groupings attached thereto. A further object of our inventionis to provide polymers in which a large number of hardening sites may beattached to the backbone of the hardener. A still further object of ourinvention is to provide polymeric hardeners which are suitable inaqueous systems such as those in which gelatin is normally used andwhich are compatible with gelatin both wet and dry. A still furtherobject of our invention is to provide polymeric hardeners for gelatincontaining both carboxyl groups and unsubstituted unsaturatedhydrocarbon terminal radicals, aldehyde radicals or maleimido radicals.Other objects of our invention will appear herein.

We have found that polymeric hardeners having a polymeric backbone andsubstituents thereon which provide (1) carboxyl groups and (2)unsubstituted unsaturated hydrocarbon terminal groups, aldehyde groupsor maleimido groups are resistant to migration from one gelatin layer toanother. These polymers incorporated in gelatin or in compositionscontaining gelatin such as silver halide emulsions will provide thelayers coated out therefrom with good resistance to melting and swell.The hardening agents in accordance with our invention have a hardeningeflect on gelatin when used therewith in almost any proportion but aproportion of at least 1% based, on the gelatin, is ordinarily mostdesirable. The optimum range for the use of the hardeners in gelatincompositions is ordinarily 510% based on the weight of the gelatin.

In its broadest aspects our invention relates to the use as hardenersfor gelatin of polymers of which the linear portion is a linearpolymeric chain having the structure of an addition polymer of thepolyhydrocarbon type or the "ice structure of a condensation polymersuch as of a polypeptide for instance gelatine (recurring CO-NH units),of a polyan-hydroglucose for instance cellulose, or of a polyamide forinstance nylon. The polymeric chain or backbone should have appendedthereto reactive groups such as hydroxyl, amino, carboxyhalide oranhydride through which the hardening groups are attached.

The hardeners in accordance with our invention are polymers havingsubstituents on the recurring units supplying carboxyl and unsubstitutedunsaturated hydrocarbon terminal groups, aldehyde radicals or maleimidogroups. It is desirable that these hardeners have a carboxyl content ofat least 3% to insure water solubility and compatibility with gelatin.They should also have at least 2% of unsubstituted unsaturatedhydrocarbon groupings, aldehyde radicals or maleimido groups orcombinations thereof in chemical combination in the polymer. Polymershaving the above described characteristics are useful as non-migratinghardeners for gelatin.

Some compounds which illustrate hardeners of this type are thefollowing:

A. COPOLY(ETHYLENE-N-ALDEHYDROMETHYL MALEAMIC ACID) n being at least 20.

B. COPOLY(ETHYLENEMALEIC ACID-MALEIM- IDOMETHYL ACID MALEATE) and x andyare 1 to 5.

c. COPOLY(ETHYLENE-BETA-MALEIMIDO- ETHYL ACID MALEATE),

D. COPOLY(ACRYLIC ACID-BETA-MALEIMIDO- 'ETHYL ACRYLATE) I dH=cH, CH3drnomcoou n where w, x, y and z are integers within the range 1-5 and nis at least 20.

3 F. COPOLY(V=INYL ACRYLOXYE'I'HYLCARBA- MATE-VINYL ACID SUCCINATE) nbeing at least 20.

Samples of the various compounds listed above were added to separateportions of a high speed gelatin-silver bromo-iodide photographicemulsion which had been panchromatically sensitized with a cyanine dye.The emulsion used contained 245 grams of gelatin per mole of silverhalide. Each emulsion sample was coated on a cellulose acetate supportat a rate of 430 mg. of silver per square foot. The coatings werecompared with controls without hardener. A sample of each coating wasexposed on an Eastman 1B sensitometer, processed for 5 minutes in KodakDK-SO developer, fixed, washed and dried. The results obtained were asfollows:

G.I100 g. Rel. Melting Hardener of Speed 7 Fog Point, Swell gelatin F.

100 1. l3 0. 12 84 772 3. 6 91 1. 12 0. 86 787 7. 2 78 l. 13 0. 08 141511 14. 4 73 1. 0. 09 177 492 3. 6 94 1. 12 0. 10 212 382 7. 2 95 1. l30. 10 212 327 14. 4 102 1. 13 0. 10 212 254 100 1. 0. 12 84 709 5. 0 890. 90 0. 22 212 414 10. 0 69 0. 68 0. 40 212 282 100 1. 08 0. 11 88 6575. 0 95 O. 97 0. 15 93 470 10. 0 83 0. 80 0. 26 183 327 100 1. 20 0. 1386 698 5. 0 74 0. 83 0. 12 212 37 9 l0. 0 89 1. 07 0. 16 212 410 100 0.98 0. 13 86 622 5. 0 91 0. 97 0. l5 212 533 10. 0 89 0. 92 0. 18 157 447100 1. 24 0. 14 86 860 5. 0 91 1. l8 0. 14 96 376 10. 0 94 1. 18 0. 13212 252 The lower speeds in the emulsions which had been hardenedappears to be due to some slowing down of the development rate ashardening action in general, does decrease the permeability of anemulsion layer to developer solution.

Examples of preparing polymeric hardeners useful in compositions of theinvention are as follows:

Example 1.-C0poly (ethylene-N-aldehydromethyl maleamic acid) A solutionof 10 grams (0.08 mole) of ethylene-maleic anhydride copolymer in 100ml. of acetone was tumbled for 3 days with 10.8 grams (0.08 mole) ofaminoacetaldehyde diethyl acetal. The viscosity of the solutionincreased marke-dly. The product was precipitated in ether, washed withether and vacuum dried giving 20 grams of product. This polymericproduct was dissolved in a mixture of 200 m1. of water and 200 ml. ofdimethylformamide and the solution was tumbled with 50 grams of ionexchange resin (Amberlite -IR120) for 3 days. The solution was filteredand the filtrate was added to 750 ml. of water containing 2 grams ofsodium hydroxide. The solution was dialyzed overnight and was thenevaporated down to 100 ml. and used for addition to gelatin compositionsfor hardening purposes. This product had an ethoxyl content of 20.7% anda nitrogen content of approximately 5%, based on the weight of theentire product. I

1 Example 2.Copoly(ethylene-maleimidvmethyl acid maleate) A solution of10 grams (0.8 mole) of an ethylenemaleic anhydride copolymer in 150 ml.of dimethylformamide was mixed with 10 grams (0.8 mole) ofN-hydroxymethylmaleimide. The mixture was heated for 2 hours on a steampot and was then precipitated in ether. The product was washed andvacuum dried and there resulted 10 grams of copoly(ethylene-male-imidomethyl acid maleate) in the form of a fibrous, whitesolid. The re action went to of completion and the product had.

2.2% nitrogen content.

Example 3.-C0p0ly(ethylene-beta-maleimidoethyl acid maleate) 6.3 gramsof ethylene-maleic anhydride interpolymer which had been heated at 120C. under vacuum overnight was placed in a glass reflux outfit equippedwith a mechanical stirrer. Eight grams of beta-hydroxyethylq maleimide,50 ml. of -hexamethylphosphoramide, '6.5

ml. of dry pyridine, and a small amount of hydroquinone were added andthe mass was heated and .stirred on a steam bath for 40 minutes to forma derived polymer.

The dope obtained was cooled and poured into two liters of ether in afine stream thereby precipitating the polymer formed. The product wasextracted with ether and dried.

in a vacuum desiccator to give 10 grams of product. Eight grams of thethus obtained product was suspended in ml. of distilled water, chilledin an ice bath and mechanically stirred, and 10% aqueous sodiumhydroxide was added dropwise, keeping the pH below 7 through-.

Poly acrylic anhydride (rather than ethylene-maleic anhydride polymer),beta-hydroxyethylmaleimide, hexa-.

meth-ylphosphoramide, pyridine, and hydroquinone in the amounts given inthe preceding example were mixed to.-

gether and treated in an identical manner. The yield of the productwas10.3 grams. Seven grams of this product was doped in 35 ml. of distilledwater in the manner described in the previous example maintaining the pHbelow 6.4. 72 grams of dope at pH 6.3 was obtained having a content of9.7% of copoly(acrylic acid-betamaleimidoethyl acrylate) Example 5.-C0p0ly(vinyl acrylate-vinyl acetatevinyl acid succinate) 22 grams ofpolyvinyl alcohol containing about 12 mole percent of combined vinylacetate were dissolved in 220 ml. of hexamethylphosphoramide by heatingto 150 C. The clear smooth dope was cooled to 50 C.

and a small amount of hydroquinone and then 20 ml. of acrylyl chloridewere added. The reaction vessel was 1 placed in a 50 C. bath and afterone hour at'this temperature ml. of pyridine and 50 grams of succinicanhydride were added and the temperature was raised to 60 C. The masswas kept at 60 C. for 21 /2 hours. The resulting dope was diluted withan equal volume of water and poured in a fine stream into 10 liters ofacetone Example 6.-C0p0ly(ethylene-beta-vinylsulf0nylethyl acid maleate)6.8 grams of vinyl hydroxyethyl sulfone was mixed with grams of a mediumviscosity ethylene-maleic anhydride copolymer, 4 grams of pyridine, 20mg. of hydroquinone and 70 ml. of distilled hexamethylphosphoramide andthe mass was heated for one hour on a steam pot. A dark solutionresulted which was cooled and poured into ether. The precipitateobtained was washed and vacuum dried. The yield was 12 grams of a lightpurple Example 10.-Acrylyl carbamyl gelatin A solution of grams ofgelatin and 200 ml. of dimethyl sulfoxide was made as in the previousexample. This was treated with 4 grams of acrylyl isocyanate. The

5 solution was allowed to stand overnight and was then i z g Y i 5 z igigifigg f g acld precipitated in acetone, giving a white powder. 6.4 m eae a y S g e a S grams of acrylylcarbamyl gelatin was obtained.

Example 7 copoly(ethylengmucochlmayl Samples of the compounds preparedby Examples 7, acid maleate) 8, 9, and 10 were added to separateportions of a high 25 2 f th 1 I h d 1 10 speed silver bromoiodideemulsion which had been grams 0 e yene f an y e ymer panchromaticallysensitized with a cyanine dye. Each and 33 gfams of mucoclflonc acldwere dlssolved m 250 emulsion was coated on cellulose acetate filmsupport at of dlmethylfolmamlde and the sqlutlon was heated a silvercoverage of 432 mg. per square foot and a gelatin 01 0 1 011 3 Steambath- The filmed darkcoverage of 980 mg. per square foot. The coatingswere It Was preclpltflted 111 ether, Washed, l'edlssolved 111 acetone,compared with controls without hardener. Each coating and reprecipitatedin ether, washed and vacuum dried. was exposed on an Eastman 1 Bsensitometer, processed A yield of 23 grams ofcopoly(ethylene-mucochloryl acid for 5 minutes in Kodak DK-SO developer,fixed, washed m-aleate) was obtained. and dried. The results obtainedwere as follows:

00110., Rel. Percent F. F. Product Example g./100 g. Speed Gamma FogSwell I Bet. MP.

of gel (Vert.)

Control--- 100 1. 34 0. 09 652 79 85 Example 1 s0 1. 11 0. 12 581 82 915 s0 1. 02 0. 14 339 None 212 10 57 94 0. 14 215 None 212 Example VII 1s7 1. a0 0. 08 678 79 89 5 7a 1. s2 0. us 568 79 89 Y 10 as 1. 21 0. 07503 79 83 Control 100 1. 5s 0. 13 sea s0 87 Example 1X 1 105 1. so 0. 13532 94 125 5 s7 1. 49 0. 11 640 None 212 10 83 1. 3a 0. 10 348 None 212Example X 1 105 1. 52 0. 1a 776 7s 83 5 105 1. 30 0. 596 s3 s9 10 so 1.34 0.24 385 86 102 water Example 8.Cop0lymer of N-acrylyl-O-mucochlorylcarbamate-maleic anhydride A solution of 50 grams of mucochloric acidand 100 ml. of acetone was added dropwise with ice cooling to a solutionof grams of acrylyl isocyanate in 100 ml. of ether under nitrogen. Themass was allowed to stand overnight whereupon a crystalline solidprecipitated. Upon cooling in a freezer and filtering, 16 grams of crudeproduct was obtained. This product was recrystallized from acetonegiving 12 grams of white needles of N- arcylyl-O-mucochloryl carbamate(M.P. 161-162 C.').

8 grams of the N-acrylyl-O-mucochloryl carbamate so prepared and 3.8grams of maleic anhydride were dissolved in 200 m1. of benzene and thesolution was heated with 0.2 gram of benzoyl peroxide on a steam pot.The mixture started to polymerize almost immediately. The mass washeated for 4 hours then the mass was cooled, filtered, washed withbenzene, and vacuum dried. A copolymer of acrylyl mucochloryl carbamateand 25 mole percent of maleic anhydride was thereby obtained (n=0.11)which product had good gelatin hardening properties.

Example 9.-Beta-acrylyl0xyethyl carbamyl gelatin A mixture of 15 gramsof gelatin and 300 ml. of dry dimethyl sulfoxide was tumbled for fourdays. Most of the gelatin went into solution. After filtering, there wasadded to the filtrate 1.5 grams of isocyanatoethyl acrylate and theresulting solution was allowed to stand overnight. It was then heatedfor one hour in a 60 bath. The product was precipitated in acetone,washed, and vacuum dried. 12 grams of beta-acrylyloxyethyl carbamylgelatin was obtained.

1 Vertical swell was determined after the strip had been immersed at 68F. in distilled The hardeners in accordance with our invention are ofspecial value for use in photographic products in which a plurality ofgelatin layers are applied one over the other because of theirresistance to migration from layer to layer. The photographic productsmay employ various types of supports such as cellulose ester film, filmof other types or paper supports, the type of support used beingoptional with the individual operator. In addition to the hardening ofphotographic emulsion layers, also contemplated is the hardening ofgelatin layers employed as overcoatings, subcoats, antistatic layers,antihalation layers or the like which layers may contain pigments, dyesor any of the other addenda which have been incorporated in gelatinlayers in the making of photographic products.

We claim:

1. A composition of matter comprising gelatin containing as a hardenertherein an efiective hardening amount of copoly(ethylene-maleimidomethylacid maleate).

2. A composition of matter comprising gelatin containing as a hardenertherein an effective hardening amount ofcopoly(ethylene-beta-maleimidoethyl acid maleate).

3. A composition of matter comprising gelatin containing as a hardenertherein an eflfective hardening amount of copoly(acrylicacid-beta-maleimidoethyl acrylate).

No references cited.

NORMAN G. TORCI-HN, Primary Examiner.

J. RAUBITSCHEK, Assistant Examiner.

1. A COMPOSITION OF MATTER COMPRISING GELATIN CONTAINING AS A HARDENERTHEREIN AN EFFECTIVE HARDENING AMOUNT OF COPOLY(EHYELENE-MALEIMIDOMETHYLACID MALEATE).
 2. A COMPOSITION OF MATTER COMPRISNG GELATIN CONTAININGAS A HARDENER THEREIN AN EFFECTIVE HARDENING AMOUNT OFCOPOLY(ETHYLENE-BEAT-MALEIMIDOETHYL ACID MALEATE).
 3. A COMPOSITION OFMATTER COMPRISING GELATIN CONTAINING AS A HARDENER THEREIN AN EFECTIVEHARDENING AMOUNT OF COPOLY(ACRYLIC ACID-BEAT-MALEIMIDOETHYL ACRYLATE).